In a technical field of molding using a mold (cast molding, injection molding or the like), to manufacture a molded product having an inner space, a molding technique has been well-known where molding is performed using a core (also referred to as an inner core or a cavity core) which has a shape corresponding to an inner shape of the inner space. When the shape of the inner space is simple, it is possible to take out a molded product using a simple molding device (for example, a molding device where a core and a molded product are linearly separated from each other simultaneously with separation of molds by projecting an ejector pin). However, in the manufacture of a molded product having an arc-shaped bent inner space, a core and a molded product interfere with each other. Accordingly, it is difficult to take out the molded product with a molding device having a simple configuration. Particularly, in the manufacture of a molded product made of metal, compared to the case where a molded product made of a resin is manufactured, it becomes further difficult to take out a molded product with a molding device having a simple configuration. This difficulty is caused by properties of metal that metal has, in general, high strength, low elasticity, a strong shrinking force (a so-called catching force) when solidified and the like compared to a resin.
As a molded product having an arc-shaped bent inner space, a part associated with an engine of an automobile, particularly, a part used for forming an intake manifold, various housings or the like are exemplified.
Due to the reasons set forth above, in a technical field of molding using a mold, there has been made steady development and studies with respect to a molding device for manufacturing the above-mentioned molded products (see patent literature 1, for example). Hereinafter, one example of conventional molding devices is described.
FIG. 13A and FIG. 13B are views for describing a conventional molding device 900. FIG. 13A is a perspective view of the molding device 900 after a molding operation is finished, and FIG. 13B is a side view of a core 930, a support member 940 and an ejector pin 950.
As shown in FIG. 13A and FIG. 13B, the conventional molding device 900 includes a pair of molds 910, 920 which is joinable to each other and separable from each other, and is capable of forming a cavity which has a shape corresponding to an outer shape of a molded product P0 in a joined state during molding. The molding device 900 also includes a core 930 which has a shape corresponding to an inner shape of the molded product P0, and is disposed in the inside of a cavity which the pair of molds 910, 920 forms during molding. The molding device 900 also includes a support member 940 which supports the core 930 from the outside. The molding device 900 also includes an ejector pin 950 which is linearly (one-dimensionally) advanceable and retractable along a direction perpendicular to a direction in which the pair of molds 910, 920 is separable from each other, and ejects the molded product P0 formed around the core 930.
According to the conventional molding device 900, the molded product P0 having an arc-shaped bent inner space can be taken out by taking, after molding, a step of separating the pair of molds 910, 920, a step of separating the core 930 and the molded product P0 together with the support member 940 from the mold 920, and a step of ejecting the molded product P0 by the ejector pin 950 in order.